Bicycle frame



FIG. 1 is a side elevational view of a bicycle frame showing my new design;

FIG. 2 is a side elevational view thereof opposite to that shown in FIG. 1;

FIG. 3 is a front elevational view thereof;

FIG. 4 is a rear elevational view thereof;

FIG. 5 is a top plan view thereof; and

FIG. 6 is a bottom plan view thereof. 

The ornamental design for a bicycle frame, as shown. 